Printer media transport for variable length media

Abstract

Printer ( 1 ) has a pivotally mounted autocompensating system ( 19 ) mounted at an intermediate position in paper guide ( 17 ). That system ( 19 ) is driven by a motor ( 40 )through a slip drive ( 70, 72, 74 ). The motor also drives paper feed system ( 15 ). When the motor turns in a direction to feed by system ( 15 ), the intermediate system is moved away from the paper guide. When a sheet reaches a position to be fed by the intermediate system, the motor is reversed, and the intermediate system pivots against the paper for moving it further through the paper guide.

1. An imaging device comprising
 an imaging station, 
 a sheet media tray spaced from said imaging station, 
 a C-shaped media guide path between said imaging station and said media tray, said C-shaped media guide path having a curve defining the C-shape, 
 a media drive member to move sheet media from said sheet media tray into said C-shaped media guide path, 
 a pivotally mounted first autocompensating system located in said C-shaped media guide path adjacent to said curve for driving media, said first autocompensating system having a slip drive located within a housing of said first autocompensating system, and 
 a reversing motor to drive said first autocompensating system, 
 whereby said reversing motor drives the sheet media in a first direction away from the sheet media tray to the C-shaped media guide path and said first autocompensating system is driven by the slip drive away from the C-shaped media guide path until rotation of the reversing motor is reversed causing said first autocompensating system to pivot to contact the sheet media and feed the sheet media to the imaging station in a second direction substantially opposite the first direction. 
 
   
   
     2. The imaging device as in  claim 1  wherein said slip drive comprises a spring mounted on a drive shaft contacting a gear whereby turning of the gear turns the spring which rotates the housing of said first autocompensating system until further rotation is blocked and the spring slips. 
   
   
     3. The imaging device as in  claim 1  also comprising a second pivotally mounted autocompensating system to feed media from said sheet media tray through said C-shaped media guide path at least to a location at which said first autocompensating system can feed said media whereby said second pivotally mounted autocompensating system is prevented by a clutch from receiving any power from said motor. 
   
   
     4. The imaging device as in  claim 3  wherein said motor also drives said second autocompensating system. 
   
   
     5. An imaging device comprising
 an imaging station, 
 a sheet media tray spaced from said imaging station, 
 a C-shaped media guide path between said imaging station and said media tray, said C-shaped media guide path having a curve defining the C-shape, 
 a pivotally mounted first autocompensating system mounted in an intermediate position in said C-shaped media guide path adjacent to said curve for driving sheet media to said imaging station, said first autocompensating system having a slip drive located within a housing of said first autocompensating system, 
 a pivotally mounted second autocompensating system to pick sheet media from said sheet media tray and feed said sheet media through said C-shaped media guide path at least to a location at which said first autocompensating system can feed said sheet media, and 
 a reversing motor to drive said first autocompensating system while operating in reverse mode and said second autocompensating system while operating in forward mode, 
 whereby said reversing motor drives the sheet media in a first direction away from the sheet media tray to the C-shaped media guide path by rotating said second autocompensating system downward while said first autocompensating system is driven by the slip drive away from the media guide path until a media-presence sensor detects the sheet media which reverses the direction of the motor causing the first autocompensating system to contact the sheet media and feed the sheet media in a second direction substantially opposite to the first direction to the imaging station while said second autocompensating system is prevented by a clutch from receiving any power from said motor. 
 
   
   
     6. The imaging device as in  claim 5  wherein said slip drive comprises a spring mounted on a drive shaft contacting a gear whereby turning of the gear turns the spring which rotates the housing of the first autocompensating system until further rotation is blocked and the spring slips.